Add @CasePathable support

[Ryu0118]

@CasePathable is added to Action via @Reducer. and Equatable conformance is no longer required.

Also I added these two syntaxes to TestStore.

let testStore = { /* ... */ } 
testStore.receive(\.receiveResponse.success) { /* ... */ }
testStore.receiveWithoutStateCheck(\.receiveResponse.success) { /* ... */ }